Process and apparatus for the separation of gas mixtures



Oct. 1-1, 1932. p. GMEUN ET AL 1,881,4 90

PRoCEsS AND APPARATUS FOR THE SEPARATION OF GAS MIXTURES Filed Dec. 27,1929 0 OOOOOOOOO OOOOOoooooOoOoooooooo O O O O O O O O O O O O O O O O OO O O O O O O O O O O O O O O O Pateuted Oct. ll, 1932 imrrao srATEsPATENT .ol-"rica PAUL GHELIN, GF EANNEEIH, .AND ADOLF KNODEL, 03' WOLEH,GEBKANY, ASSIGH- GBS T0 I. G. FABBENINDUSTBIE AKTIENGEBELLBCEAF, OFFBANKFQRT-ON-m mm, GERMANY FROCESS .AND APABATUB Em EPmATIQH O? GAS www.npplieetiou med Decemher gt, me, Seria! Ro.. M6310, and in Germanymcember 31, 1838. i

. The present invention relates to a process and apsparatus for theseparation of gas mixtures y difiusion.

The'economical s-eparation of the single components from mixtures ofgases or vepors is frequently oi great importance industrially Whetherit be :tor the purpose of removing undesirable components or for thepurpose of recovering the veluahle components in a pure or a more orless concentrated form. 'l`he processes already known for this purpose,especially those which depend on the employment oi a solvent 'for thecomponent to be separated usually necessitate expensive and troublesomeplants, and -irequently leed to great losses' of the solvent employed,especially When it is desired to recover valuable components 'fromdilute mixtures. The processes Which depend on the difiusion of thecomponents to he separated through porous Walls or by means of fiorvingassistant gases are likewise too costly, or in the case of theemployment of assistant difiusing gases or vapors, the processes havethe disadvantnge that the said assistant gases or vapors ore to beproduced in o separate epparetus or must be compressed to produce thehigrh` speed oi' assistant gas necessary for cerrying out the process.

'We have now found that in many esses o fer going separetion oi mixturesof gases or vapors iney be eifected inte Very econornioel manner bycontacting the gets misture With s yaporous diiiusing agent producecl'byevaporating a liquid in contact with the nas mixture and removing therepor and the components of the gas misture difiused therein from theeveporating liquid. 'ln order to ensure good vaporization as great esurface as possible is imperted to the liquid, for example by ellowi'ngthe preiiersbly preheateol liquid to triclle ldown over distributinghodies, disposed in the difiusion npparatus in a layer dividing theapperutus into two compartments, the gas mixture being pussed along oneside of said layer ond the `repor and the components of the gas misturedifiused therein heing withdrawn from the other side. The gas mixture tohe separated is preferubly also preheated to temperoture slightly abovethe temperature at which the liquid is veporizecl. The removal of thevapor from the vaporizing liquid is preferably efiected by the insertionof cooling means on Which the vapor condenses 'Whereo by the vaporcarries with it the components of the gas mixture difiused therein. Thediffusion may be regulated by verying the temperature at Which theliquid is vaporized, the pressure under Which the gas misture issupplied, and the pressure under Which the Vapor containing thecomponents difiused therein, or, in case the vapor is condensed Withinthe difiusion apparatus itself, the pressure under Which the saiddifivused components are Withdrawn. The pressures, however, under Whichthe gos misture 'is supplied on the one hand und under Which the vaporcontaining the components difiused therein, or under Which the soldcomponents themselves after condensation oii the vapor, ore Withdravvu,should not difi'er very much irem eech other.

The nsture of the invention Will he 'further described With reference tothe accompenying* drawing Which shows diogremrnatically in verticalsection an errangernent of apperotus-according to this invention, hntthe invention is not restricted to this arrengement.

The gos Inixture to he seperated is introu Wire netting or pertoratedsheet motel or the like, Worm `Water for 'example Vis allowed I tricklefrom s supply apparatus 'W end this V on its Way from the top-fito thebottom of the filling l' is psrtly yeporized, the non-'vapcrized portionflowing out through the pes- Sage A. (ln the one hand the velocity offlow or the pressure or the gas mixture introduced at E end on the otherhand theamount end the temperature of the water triclrling down, or theamount-and temperature of the cooling medium tlowing through the coolingtube K may he readily regulated so thet the Water vapor formed in thespace F streams against the said tube K With such a velocity and iscondensed thereon that it carries with it to the cooling tube a greatpart or the majority ,of that component of the gas mixture to beseparated Which difi'uses more quickly into it. The gas which is thusremoved from the region of the vaporizing Water and which is freed fromwater vapor by streaming along past the cooling tube K is withdrawnthrough the passage D, while the component of the gas mixture which hasnot difi'used is led through the tubes `C.

In order to efiect a sharp separation of the gas misture it isfrequently advantageous to impart a cyclonic movement to the introducedgas misture or even to the non-dilfused component which is flowing away,and this is preferably eifected by means of supply 'and withdrawal tubeswhich are inclined to the vertical axis of the cylinder. ln order toprevent any injurious infiuence of the streaming of the introduced gasmixture on the difi'usion process it may be expedient to break up thestream into fine eddies by nets, defiecting plates and the like arrangedin a suitable manner on the casing of the filling. A bundle of tubes ora tubular Worm, pref-l erably wound in a close Spiral, may be employedinstead of the cooling tube K.. The freeing of the separated componentfrom the vapor of the liquid may also be efiected or assisted byadsorption or absorption of the vapor, for example by replacing thecool-- ing tube by allowing a solid or liquid agent which will adsorb orabsorb the vapor to trickle down or by arranging a layer of such anagent between the cooling apparatus and the vaporizing apparatus. Thegas mixture to be separated is preferably 'heated to the temperature ofthe liquid to be vaporized or better still to a somewhat highertemperature. This can be effected in any suitable manner, for example bythe employment of the heat of the gases and liquids leaving theapparatus Which is recovered by heat exchange. This heat may also beemployed for heating the liquid to be vaporized which is preferably ledin a cycle.

If one operation is not suflicient, the process in accordance With thepresent invention may be readily carried out in a cycle orlin severalstages or by the employment of both these methods. The operation instages is carried out so that the working conditions, such astemperature, velocity of flow of the lgases and the liquid which istrickling down,

or the kind of liquid are changed each time, and this is especially-useful when it is desired to treat gas mixtures Which have more thantwo components.

The process according to the present invention has proved veryadvantageous for example for the separation of mixtures of carbonmonoxide and hydrogen, and among essa-iso others may be mentionedtheselaration of acetylene and similar hydrocar ons ,from

The separation of such gas mixtures is rendered even more eflicient Whenliquids which .have a special dissolving power for one or more of thecomponents to be separated are employed as the liquids to be vaporized.in many cases it is advantageous'to employ the Ordinary organicsolvents, for exam le ether, alcohols, acetone, benzene and the li e.

The objections peculiar to the processes already known, which can betraced back to the employment of thick layers of liquid and highpressures for dissolvin the gases in the liquids, or to the greatresistance and the danger of clogging when employing diflusion cells,are avoided by the process in accordance with the present invention.'With a greater efficiency .the new process requires only a smallexpenditure of energy and heat because the expensive compressionoperation is dispensed With and in most cases a comparatively lowtemperature suifices to evaporate suficient amounts of vapor.

The following example-will further illustrate how the invention iscarried out in prace tice but the invention is not restricted thereto.Example A gas mixture consistiu of 72 per .cent of hydrogen and 28 ercent o nitrogen is passed 'at about atmosp ieric pressure through theapparatus described and shown having a capacity of 8 liters per minuteand fed per minute with 12 cubic centimeters of water of C. By assingthe said gas mixture once through t e apparatus a gas mixture consistingof 82 per cent of hydrogen and 18 er cent of nitrogen is obtained in ayiel of 15 per cent of the initial gas mixture employed. The differencein pressure between the incoming and the issumg gas mixtures amounts toabout 1 millimeter of A a water column. i

By passing the issuing gas mixture a second time through the apparatusunder the same conditions a gas mixture of a hydrogen content of about92 per cent is obtained in a yield of over 40 per cent.

By passing a gas mixture consisting of 25 per cent Yoffcarbon dioxideand 75 per cent of hydrogen through the apparatus under the sameconditions a as mixture c'onsistingof 91 per cent of hy rogen and 9 percent of carbon dioxide is obtained in a yield of 15 per cent.

When employing ethyl alcohol instead of Water 15 per cent of a gasmixture consisting of 88 per cent of hydrogen and 12 per cent of carbondioxide is obtained.

What we claim is a 1. A process for the separation of gas mixmemso tureswhich comprises passing a gas mixture along one side of a la er'of atmckling and vaporizing liquid an removing the va os and the componentsof said gas mixture iffused therein from the other side of said layer,and separately withdrawing the remaining components of the gas mixture.

2. A process for the separation of gas mixtures Which comprises passinga gas misture along one side of a layer of a trickling andvaporizingliquid,condensingthe vapor on the other side of saidlayer,.removing the uncondensed gas having difiused into said vaporsfrom the said other side of said layer, and separately withdrawing theremaining components of the gas mixtni'e. V

3. Apparatus for separating gas mixtui'es comprising a, Vessel, aVertically disposed layer of distributing bodies dividing said Vesselinto two compartments, means for supplying a liquid at the top of saidlayer, means foi: passing gases into one of said compartinents and meansfoi' withdrawing gases from each of said two compartments..

4. Apparatns foi? separating gas nlixtnres v coinprising a Vessel, avertically disposed layer of distribnting bodies dividing said Vesselinto two compartlnents, means for supplying a liquid'at the top of saidlayer, means for passing gases into one of said compartnients, a coolingdevice in the other compartinent and means foi' withdrawing gases fromeach of said two compartments.

5. Appai'atus foi' separating gas mixtnres coniprising a cylndricalVessel, a concentric vertically disposed layer of distrihuting bodiesdividing' said Vessel into two compartments, means foi' supplying' aliquid at the top of said layer, means foi: 'passing gases into theouter compartrnent and means foi: Witlidi'awing gases from the inner andoute'f compartnients.

6., Apparatus for separating gas mi'xtures comprising a eylindricalVessel, a concentric vertically disposed layer of distributing bodiesdividing said Vessel into two compartments, means foi' supplying aliquid at the top of said layer, means foi' passing gases into theontencompartment, a cooling device within the inner compartment andmeans foi' Withdrawing gases from the ier.

and outer compartments.

In testimony Whereof We have hereunto set our hands.

PAUL GMELIN.,

GLF MODEL.

